自锁托槽非拔牙矫治下牙列拥挤的临床研究

目的 比较自锁托槽和传统结扎式托槽非拔牙矫治牙列拥挤患者的下牙列变化,探讨自锁托槽解除牙列拥挤的机制.方法 选择26例下牙列拥挤患者,分为自锁组和传统组,每组13例,分别使用自锁托槽(Damon3)和传统托槽(传统结扎式托槽)进行非拔牙矫治.对矫治前后变化进行配对t检验,逐步回归分析拥挤解除机制以及影响下切牙唇倾度改变量的相关因素.结果 矫治前后两组患者下颌尖牙间、前磨牙间牙弓宽度改变量及下切牙唇倾度改变量比较,差异均无统计学意义(P>0.1);矫治后自锁组下颌第一磨牙间牙弓宽度增加1.42 mm、下切牙凸距增加2.66 mm,传统组下颌第一磨牙间牙弓宽度增加0.65 mm、下切牙凸距增加1.57 mm,两组比较,差异有统计学意义(P<0.1).回归分析显示,自锁组对下切牙唇倾度变化量解释的总测定系数高达96.6%,被选入模型的变量为矫治前下颌拥挤度、下颌平面角、第一磨牙间牙弓宽度,以及矫治前后尖牙及第一前磨牙间牙弓宽度改变量.结论 非拔牙矫治下牙列拥挤时,自锁组和传统组患者均出现下切牙唇倾及下牙弓宽度增加,自锁组第一磨牙间牙弓宽度增加量及下切牙前移量较传统组多;自锁组下切牙唇倾度的改变不仅受拥挤度和矫治前牙弓宽度影响,而且受患者自身骨面型及牙弓宽度变化的影响.

Non-extraction treatment with self-ligating and conventional brackets

Objective To compare the dental change and the mechanism after non-extraction treatment between passive self-ligating and conventional bracket systems. Methods Twenty-six non-extraction crowding cases were selected. Half of them were treated with Damon3 self-ligating brackets and the others were treated with conventional brackets. The results were compared. Stepwise regression analysis was performed for the two groups. Results There were no statistically significant differences in the changes of the intercanine and interpremolar widths and L1-MP angle(P > 0. 1 ). In the self-ligating bracket group, the intermolar width increased by 1.42 nun and the L1-Apo increased by 2. 66 mm. In the conventional appliance group, the intermolar width increased by 0. 65 mm and L1-Apo increased by 1.57 mm. The differences were statistically significant between the two groups ( P < 0. 1 ). Stepwise regression analysis showed that in self-ligating bracket group, the coefficient of determination for the changes of L1-MP was 96.6%. Conclusions In crowding cases treated with non-extraction, there were an overall increase in theproclination of the mandibular incisors and the arch width in both bracket groups. Compared with cases treated with conventional appliances, the cases treated with Damon3 brackets resulted in greater intermolar width increases; In Damon3 bracket group, the change of the lower incisor inclination was influenced not only by the mandibular crowding and the intermolar width before treatment hut also by the patient's skeletalpattern and the changes of the arch width during treatment.